In their first face-to-face meeting, US Senator Scott Brown and his Democratic rival, Elizabeth Warren, face delicate challenges: She must engage him on issues without seeming aggressive; he must fend off her charges without hurting his likable image.

Brown and Warren are set to take the stage in a Boston television station Thursday evening, stripped of their political handlers and media specialists. The debate, which will give the public its first unspun look at how they handle themselves, is scheduled to air live on WBZ-TV (Channel 4) and C-SPAN at 7 p.m.

The two will face a difficult balancing act, analysts say. Warren is strong on substance and in step with many voters on the issues, but she can also come across to some as a wonk and even preachy. Brown is seen as approachable and popular with voters, but must work to show that he has policy chops.

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“What will determine what happens is how they handle the issues in the debate and who takes control of it,’’ said Tad Devine, a Washington-based Democratic media consultant with extensive experience in Massachusetts races. “One [Brown] is style, the other is substance. Often style can trump substance.’’

After a year of campaigning, Thursday’s debate will mark the first time that Brown and Warren have faced off in public. Moderator Jon Keller will ask questions, with Brown and Warren, standing at podiums, engaging in direct exchanges. There are no panelists. Keller will referee.

How they perform in an unwieldy format could set the course for the final stretch of one of the most closely watched races in the country.

Some analysts say Warren, in particular, could have trouble connecting with voters. Her advisers are counting on her to win the debate on the issues, but at the same time, not to lose ground on tenor and delivery.

“It’s a difficult dance,’’ said Paul Watanabe,
a political science professor at the University of Massachusetts Boston. “In going after Scott Brown, she may not display a personable and likable side of her.’’

Presidential elections have long turned on debate styles. In 2000, Al Gore loomed over George W. Bush in gravitas, but turned off voters with what appeared to be aggressive arrogance, a sharp contrast to Bush’s casual, friendly style. Gore’s standings in the polls dropped in the days that followed and never really recovered.

Warren, while indeed experienced in academic and legal debates, has hardly been tested in the heat of a live televised political matchup in which so much is at stake.

Her reputation as an articulate law professor who can boil complex legal issues into easily understandable concepts will be sorely tested in a heated political arena, as she spars with a savvy political incumbent who can throw quick and easy barbs that put his opponents off-step.

Brown, too, will face challenges. Watanabe said he has been able during his short tenure to project himself as an amiable and approachable political figure. But his Republican credentials and his support for some national GOP initiatives seem to be hurting him, according to several recent polls.

“The latest polls seem to give some indication that the public can separate the two issues,’’ Watanabe said, referring to four recent surveys that show him trailing Warren, despite having a higher favorability rating. “Brown remains very popular with voters, and yet on the other hand, in a head-to-head race, Warren gets the majority of their votes.’’

A fifth recent poll, released Wednesday night, showed Brown leading 49 percent to 45 percent among those deemed likely to vote. (Story, B3.)

Devine says Brown’s experience can play to his advantage.

“Brown has clearly demonstrated he has real skills when presenting himself to the public,” he said. “His advantage is that he has shown he can perform on a big stage and connect with the voters. Brown needs to continue to be the guy who speaks the truth to power and can stand up for voters.’’

Indeed, Brown has outperformed debate expectations in previous elections. His debates with Attorney General Martha Coakley in the final days of the 2010 special election to fill the late Edward M. Kennedy’s seat helped him to seal his victory.

It was in one of those debates that he made the famous comment, “it’s not the Kennedys’ seat . . . it’s the people’s seat.” The quip energized his eclectic base of Republicans, Tea Party activists, and conservative Democrats.

While advertising and media hype can play critical roles in shaping voter opinions, debates, some political veterans say, are equally, if not more, important. Voters, they say, understand that ads are one-sided and look to debates to give them an unfiltered view of the candidates.

“Debates give you the real deal, candidate against candidate, without proxies in between to do the dirty work for you,’’ said Rob Gray, a veteran Republican political consultant. “Now we get to see the two of them in true light.’’

Both candidates head into the debate with some wind at their backs.

Brown has flooded the television airwaves with feel-good ads that have reinforced his image as easy-going, while making no mention of Republican affiliation.

Warren has come out of the Democratic National Convention, where she had a prime-time speaking spot, on a roll. Four of the five polls released this week show her edging past Brown.

But each campaign has tried to pose its candidate as the underdog, promoting the skills of his or her opponent in an effort to temper expectations.

“She’s representing Harvard now, has been there teaching, lecturing, and debating at Harvard,” Brown told reporters Monday. “She went to college on a debating scholarship, so I’m going to have my hands full. But I am going to work hard, as I always do, and make sure I can tell people the very clear differences about who we are and what we stand for.”